Flora of New Zealand Series

Lectotype: New Zealand. South Island, Otago, Dunedin, St Clair, on coastal rock, J.S. Thomson T 1001 [ZA 36] – CHR 373792 [fide Galloway (1985a: 65)]. Isolectotypes – OTA 029492, W.

Description : Thallus thin, closely attached, continuous, areolate, spreading in irregular patches, 1–2(–4) cm diam., with or without a thin, arachnoid, pale creamish yellow prothallus, visible between areolae and sometimes also extending 2–5 mm beyond the margins as a bordering fringe. Areolae small, angular, 0.2–0.8(–1) mm diam., separated by fine, narrow cracks, surface convex to plane, matt or glossy in parts, golden-yellow to mustard-yellow, or yellow-orange (appearing orange from a distance), often ±blackened. Apothecia prominent, numerous, often covering large areas of thallus, scattered to clustered, minute, (0.05–)0.1–0.6(–1.0) mm diam., sessile; disc orange-yellow (more golden-yellow than orange), matt; thalline margin not apparent, restricted to a thin collar or minute clustered granules at margins and base of disc; proper margin persistent, entire, thin to slightly swollen and raised, concolorous with or paler than disc. Epithecium yellow, densely granular, 12–16.5 μm thick. Hymenium colourless, without oil droplets (60–)70–85(–92) μm tall. Paraphyses slender, 1.5–2 μm thick, apices swollen to 4–5 μm diam., submoniliform. Asci cylindrical (40–)55–75 × 12–17.5 μm, 8-spored. Ascospores biseriate in ascus, oblong-ellipsoid with rounded apices, (12–)14–16(–17) × (5–)6.5–7.5(–8.3) μm; septum 3.5–5 μm thick, ¼ to ⅓ length of spore.

N: Wellington (Kapiti, I., Titahi Bay). S: Canterbury (Banks Peninsula, Dashing Rocks Timaru), Otago (Cornish Head, Long Beach, Kaikai Beach, Tomahawk, Boulder Beach Otago Peninsula, St Clair Dunedin, Black Head, Bruce's Rocks, Brighton, Taieri Beach, Akatore, Nugget Point, Hinahina, Jack's Bay, Cannibal Bay). Southland (Deas Cove, Secretary I., Cosy Nook, Pahia Point, Howells Point, Bluff). St: (Bathing Beach Halfmoon Bay, Port William, Noble I., Port Pegasus). Ch: (SW of Waitangi). Ant: C: (Tucker Cove). On smooth, hard, coastal rocks at high tide mark or above. Also on concrete retaining walls and paths in coastal habitats. Associating with: Caloplaca rosei, Carbonea phaeostoma, Dirina neozelandica, Opegrapha diaphoriza, Pertusaria graphica, Rinodina thiomela, Tylothallia pahiensis, Verrucaria maura. Apothecial discs are often parasitised by a species of * Polycoccum.

?Endemic

Illustration : Martin & Child (1972: 111. pl. 23).

Caloplaca circumlutosa is characterised by: the saxicolous habit (coastal rocks); the thin, closely attached, areolate, golden-yellow to mustard-yellow or yellow-orange thallus, with a thin, arachnoid pale yellowish prothallus visible between areolae and often also projecting from the thallus margins; minute apothecia; and oblong-ellipsoidal ascospores, (12–)14–16(–17) × (5–)6.5–7.5(–8.3) μm; septum 3.5–5 μm thick, ¼ to ⅓ length of spore.